
public class Stack3 {
   public static void main(String[] arg){
	   try{
		   c();
		   
	   }catch (NullPointerException ex){
		   ex.printStackTrace();
	   }
   }
   
   
   static void c(){
	   try{
		   b();
	   }catch(NullPointerException ex){
		   ex.printStackTrace();
		  Throwable t = ex.fillInStackTrace();
		  throw (NullPointerException) t;
	   }
   }  
  
   
   static void b(){
	   a();
   }
   static String a(){
	   String text = null;
	   return text.toUpperCase();
   }
}
